X-ray tube



Jan. 2, 1934.

L. F. EHRKE X-RAY TUBE Filed Oct. ll, 1950 INVENTOR L f.- EHR/f5 BY j 27% f ATToRN Patented Jan. 2, 1934 UNITED Y STATES PATENT orio X-RAY TUBE tion ef Pennsylvania lApplication October 11, 1930. Serial No. 488,008

1 Claim.

This invention relates to X-ray devices and more particularly to X-ray devices useful in the therapeutic application of X-radiations to living tissues, and still more particularly to a type of VX-ray device Which may be introduced within body cavities.

I-Ieretofore in the art the therapeutic application of X-radiations to interior portions of the body has been exceedingly difficult and such radiations as have been applied have been obtained from X-ray devices positioned exterior to the body, the X-radiations traversing the body tissue interposed between the X-ray device and the portion of the body to be acted upon by the X-radiations.

It is highly desirable to provide an X-ray device that may be introduced within body cavities and safely operated therein Without deleterious results to either the patient 'or to the device.

It is one of the objects of the present invention to provide an X-ray device which may be introduced Within body cavities.

It is another object of this invention to provide a new type thermionic X-ray device.

It is another object of this invention to facilitate the application oi X-rays.

Other objects and advantages Will be apparent as the invention is more fully disclosed.

In accordance with the objects of my invention I have devised an X-ray device having an elongated tubular end portion adapted to be introduced within a body cavity, Within which end portion is incorporated the cathode, anode, and anode shield member, axially disposed in such manner that the X-radiations pass out of the device through the end thereof.

I also provide means exterior end portion to electrically shield the same so that deleterious electrical discharge from the tube to the body of the patient cannot take place. In order to accomplish the objects of my invention I have also devised a novel type of X-ray device which Will be more fully hereinafter disclosed.

Before further disclosing the nature and scope of the present invention reference should be made to the accompanying drawing wherein Fig. 1 discloses in side elevational cross sectional vievv an X-ray device constructed -ln accordance with the present invention;

Fig. 2 is a cross sectional view taken along plane II-II Fig. 1;

Fig. 3 is a cross sectional View taken along plane III-III of Fig. l;

to the elongated Fig. 4 is a cross sectional View taken along plane IV--IV in Fig. 1; and

Fig. 5 is a cross sectional view taken along plane V-V Fig. 1.

Referring to Fig. 1 an X-ray device constructed 6Gr in accordance with my invention comprises an enclosing tubular envelope 1 having a reentrant stem member 2 ending in a press 3 through which extends a leading-in Wire 4 connected by flexible conductor 5 to anode 6.

Anode 6 is an elongated cylindrical copper electrode extending axially along the longitudinal axis of the tubular envelope land terminating in a target element 7 which is adapted to emit X-rays when bombarded by thermionic elec- 705 trons.

Anode 6 is retained in fixed axial position by means of spring collar member S adapted to frictionally engage the interior of the element l in the manner shown. Means 9 comprising a col- 751, lar adapted to encircle the anode 6 andto be rigidly united thereto as by screw 10, is provided to unite the anode to the spring collar member 3.

A thermionically active cathode l1 is positioned in spaced relationship to the target end '7 of the 55', anode electrode 6. The cathode may be comprised of tungsten, tantalum or other type refractory filament and is preferably mounted in a focusing cup element 12. An X-ray absorbing anode shield member 13 is provided to intercept 85" X-radiations traveling in any direction except along the longitudinal axis of the device. This shield member is also a split clip element frictionally engaging the interior Wall of the envelope and extends along the tubular envelope towards 9@ the anode end ofthe device a distance determined by the desired length of the elongated section of the cathode end of the device. VThis anode shield element may be made to serve as a leadingin conductor to one end of the lament 11 and 95 also to serve to support the focusing element 12 in the manner shown. v Y Y The other end of the iilamentary cathode 11 is insulatingly carried through the focusing cup member l2 in the manner illustrated at 14 to 100 a leading-in support wire 15 extending longitudinally the length of the elongated end portion Within the slotted portion of the shield member 13 to be electrically connected to leading-in wire 16. An oppositely disposed leading-in Wire 17 is m5 electrically connected to the anode shield member 13 in the manner shown.

With this type of construction the X-radiation emitted by electronic bombardment of the anode target 7 is restrained from egress in any direc- 110 longitudinal axis of tion except along the longitudinal axis of the device towards cathode 1l which is shaped so as to permit the passage of the X-rays therethrough.

It is apparent that while I have shown the arrangement of elements whereby I may therapeutically apply the X-radiation emitted along the the device, I am not necessarily limited to this particular assembly, as it is obvious that I may provide an opening in the shield member 13 in such position for example that the X-radiation may be taken off in a direction substantially at right angles to the longitudinal axis of the device.

To permit the egress of X-radiation of the longer wave lengths when relatively low voltages are employed a thin glass window 18 of the type heretofore disclosed in U. S. Patent No. 1,735,302 issued November 12, 1929 to C. M. Slack, may be employed and the X-ray absorbing shield member may be disposed with respect to the anode so as to substantially block off all X-rays except those striking the thin glass window 13. When higher anode voltages are employed the X-radiation of shorter wave length will penetrate glass of the thickness customarily employed in X-ray devices, and the thin glass window 18 may be dispensed with, if desired.

The X-ray device may be of the evacuated type or may have an inert-gas lling, such as neon up to approximately 2.5 microns of mercury pressure, if desired. The constructional features of the assembly of the elements of the device may be more readily determined by an examination of the cross sectional view of Figs. 2, 3, 4 and 5 wherein the elements above identified are clearly identified by their respective numerals.

It is to be noted in Fig. 3, for example, that the method of positioning and supporting the leading-in support wire l5 in fixed spaced relationship with the edges 19 and 20 of the slotted portion of the anode shield member 13 is shown. An electrically insulating element 21 encircles the leading in wire 15 and the; combination is rigidly retained in position on the shield member 13 by means of grip members 22 attached to said shield member in any convenient or desired manner.

As shown in Fig. 1, shield member 13 is comprised of a split ring member adapted to engage the interior walls of the glass envelope 1, about the anode target member 7. This shield member is tapered to a tubular section as is illustrated terminating in an end portion 12 adapted to serve the purpose of a focusing cup as may be clearly noted in Fig. 2.

Referring to Fig. 4 the relative spacing of the elements along plane IV-IV Fig. 1 may be readily noted. In Fig. 5 the spring grip method of mounting the anode is illustrated with particularity.

It is believed apparent that the overall dimensions of the device contemplated bythe present invention would be dependent upon the contemplated use thereof and upon the desired electrical characteristics of the device. The X-ray tube may be made extremely small or it may be made larger and it may be a vacuum device or a gas lledX-ray device. The electric potentials to be applied to the anode depend in major part upon the type of X-radiation desired.

In any adaptation of the present invention the advantage to be gained by the use of the X-ray device herein illustrated having an elongated cathode end arises largely from the application of the X-rays to some internal region of the body of a patient over a relatively narrower region than heretofore permissible when the X-ray device is entirely outside of the body. It also enables the operator to irradiate a specific part of the body with greater intensity without subjecting the surrounding parts to excessive irradiation.

In order to fully protect the patient from deleterious electrical discharges the exterior surface of the elongated cathode end of the device should be covered in any convenient manner with an electrically conducting shield member such as is disclosed in copending application Serial No. 488,592 led October 14., 1930, assigned to the same assignee as the present invention, which should be substantially at ground potential.

Instead of having a straight elongated cathode, and as indicated in Fig. 1, the end may be slightly curved, if desired, so as to facilitate its use and application in therapeutic work.

It is believed apparent that there may be many modications and departures made of the present invention without departing essentially from the nature and scope thereof as illustrated in the specication and drawing, and such modifications and departures are anticipated as may fall within the scope of the following claim.

What is claimed is:

An X-ray device comprising a gas-tight dielectric enclosing envelope, an elongated anode having a target end and a cathode within said envelope, an elongated supporting means associated with said anode and having a portion thereof in frictional contact with the inner wall of the envelope and adapted to support said anode, an X-ray screen means housing the target end of said anode, a focusing cup carried by said screen and housing said cathode, a portion of said screen means being resilient and surrounding and spaced from said anode, the resilient portion of said screen means having the outer surface thereof in frictional contact with the interior surface of said envelope, a plurality of cathode leading-in conductors hermetically sealed to the envelope, one of said leading-in conductors being elec trically connected to the upper portion of said screen means and to one side of said cathode and the other leading-in conductor being connected to the other side of said cathode.

LOUIS FREDERICK EHRKE. 

